68718952447domain: NAppears in sequencesPrimes of the form 4^k - 2^(k+1) - 1.at n=8A091516a(n) = (2^n-1)^2 - 2.at n=17A093112Primes of the form q*2^h - 1, where q is a Mersenne prime (A000668).at n=30A335874Numbers of the form (2^k-1)^2 - 2 that are squarefree.at n=15A381698